Inflatable airbags are commonly used to protect persons in a vehicle, such as a car, bus, lorry or truck, in case of an accident. An airbag arrangement comprises a deployable airbag and a gas generator arranged to supply gas to deploy the airbag.
A known type of airbag arrangement according to prior art is described below in conjunction with FIGS. 1 and 2, wherein the airbag arrangement is used as a side airbag arrangement. Upon initiation of the gas generator, a gas flow expands radially away from the top of the gas generator in a plurality of arbitrary directions. During deployment the airbag repels against a supportive structure, which is attached to a seat frame, and the seat frame itself, and expands laterally and longitudinally in the vehicle. The airbag also interacts with a hardback of the seat during deployment. The airbag further interacts with a door, b-pillar and panel at the side of the vehicle during deployment. Much volume is deployed in a very short time. The deployment of the airbag may lead to high forces against the parts of the seat, e.g. against the hardback.
Document US 2011/0285119 A1 discloses a side airbag system and a method of manufacturing a side airbag arrangement. The airbag arrangement comprises an upper airbag portion and a lower airbag portion divided by a tether portion. A tube, which distributes gas between the upper and lower airbag portions, extends through the tether portion to the upper and lower airbag portions. In one embodiment, the gas generator is arranged inside the tube, which is inflated prior to the upper and lower airbag portions.
However, since the tube of document US 2011/0285119 A1 extends in a substantially vertical direction, the airbag will reach its vertical deployed extension before being fully deployed longitudinally in the desired direction, which is substantially forwards in the vehicle. There are further similar risks as described above for high forces against the parts of the seat.
U.S. Pat. No. 7,597,351 B2 discloses a side airbag arrangement comprising an airbag and a gas generator. The gas generator emits gas from one end only, directed in a longitudinal direction of the gas generator.
However, since the gas generator of U.S. Pat. No. 7,597,351 B2 is mounted at the seat with the longitudinal direction of the gas generator along the direction of the backrest of the seat, i.e. close to a vertical direction, the gas flow will be substantially vertical. Therefore the airbag will reach its vertical deployed extension before being fully deployed longitudinally in the desired direction, which is substantially forwards in the vehicle. There are further similar risks as described above for high forces against the parts of the seat.